Friday, 7 December 2007

A laptop for every school?

Before we all go soft in the head over the idea of a latop in every school, let's examine the cost of having to provide a network for a school of say 900 kids.

If all 900 have a PC or laptop, and it needs to be used for every lesson, then you need at least 900 network ports - more like 1000 when you include things like printers and other peripheral devices that you might add in like scanners, security cameras and spare ports.

There are three components to your network.

The physical cabling. We'll get to that later.

A router, which you need to connect to the outside world.

A switch, or more likely, a bunch of switches.

You can setup your network in two ways. One is to stick a switch in every classroom. An example of that would be a Cisco 3750 with 48 ports. That retails for around $15,000 ex GST.

If you have 900 kids and say 25 per class, you have at least 36 classrooms. That means you need $540,000 worth of switches at a minimum - and this does not include the core switch that these 36 classroom switches need to connect to.

Now a canny education dept would be able to negotiate a good bulk discount, and get them for say 40% off retail. That still adds up to $324,000.

The problem with a network like this is that it will suffer from congestion. The better alternative is to put in some big, beefy switches at the core. This is how big companies do it. To do that, you need something like a Cisco 6509 switch.

I am not going to include all the components here, but this gives you an idea of what a big switch retails for:

6509 9 slot chassis - $15,675. This is just the "box" that everything else slots into.

6000W power supply - $8,250. And you need two of them per chassis. You also need special 16A power circuits for them, so you have to pay a sparky to do some work before you can think about installing them.

Supervisor module - $42,000. This is the "brains" of the switch. Many companies like to fit two, so you have redundancy.

48 port module - $12,375. This is what your computers actually plug into. Assuming you jam 6 into a chassis, each switch will give you 288 ports.

So for a school of 900, you are going to need 4 switches. Each one will cost you $190,000, and that does not include the cost of all the "minor" bits that I didn't bother including for the sake of brevity. Even with a fat discount, you will still be up for $150,000 per switch, or $600,000 to do the school.

These things pump out a lot of heat, so you need a special room for them. You can fit two into a rack, and each rack will cost at least $2,500. The room will need air conditioning 24x7. I'd also secure it properly, since that room now contains the most valuable things in the school.

These things are complicated. You will need to pay a smart techo to install and configure them. Ddon't even think about one of them getting out of bed for less than $20,000 on a job like this.

Then let's think about cabling. Even if you put in CAT5, you can still expect to pay $0.60 a metre, and you will need a lot of cable, and you will need qualified people to pull it and terminate it. I am not an expert on estimating what it would cost to cable a school, but let me just throw up a figure of $250,000 for an average school with a need for 1000 ports spread over multiple buildings.

So you are looking at well over $600,000 so far just to network the school. I haven't estimated what it will cost to provide the extra power points, or the support to keep it all running.